Medical retrieval devices generally are used to retrieve material, such as a stone, from a body tract or to stabilize material in a body tract for fragmentation by a lithotriptor, such as a laser lithotriptor. In existing medical retrieval devices, the retrieval assembly, such as a basket, is formed from a plurality of wire legs or loops, or by a fabric, such as a metallic fabric or mesh. The retrieval assembly is used to capture material such as a ureteral, urethral, renal, biliary or gallbladder stone. Once the stone is captured in the basket, an attempt is made to remove the stone by withdrawing the medical retrieval device from the body while the stone is captured in the retrieval assembly.
In some clinical situations, a stone located within a body tract is too large or too jagged to be withdrawn from the body tract while captured in the retrieval assembly of a medical retrieval device. Under these conditions, the stone must be fragmented into smaller particles.
When stones are fragmented within a body tract by a lithotriptor, the stone must first be stabilized. Typically, a medical retrieval device is used to capture a stone in the retrieval assembly. With the stone held in position within the retrieval assembly, a lithotriptor, such as a laser lithotriptor, comes into proximity with the stone and the stone is fragmented by the lithotriptor. After the stone is fragmented, the stone fragments can be removed by the same or a different medical retrieval device, or the fragments can be left in the body to be eliminated naturally.
Laser lithotriptors have gained increasingly wide application in the treatment of stones that are lodged within a body tract. Several lasers, such as the Nd:YAG laser and the holmium:YAG laser, have become available for medical applications.